Sideboard



FIG. 1 is a top perspective view of a sideboard, showing my new design in a first position of use with the doors of the article closed;

FIG. 2 is its a second top perspective view thereof, shown in a second position of use with the doors of the article open;

FIG. 3 is a front view of the sideboard, shown in the first position of use;

FIG. 4 is a rear view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a top view thereof; and,

FIG. 8 is a bottom view thereof.

The broken lines in the drawings illustrate the portions of the sideboard, which form no part of the claimed design. 

CLAIM The ornamental design for a sideboard, as shown and described. 